Problem-posing is effective learning for comprehending problem structure. We have designed and developed the learning environment for problem-posing and performed its practical use for first and second grade students on elementary school continually. The scopes of these systems are one-step addition, subtraction or multiplication arithmetic word problem. The results of these practical uses suggested that the learning environment was effective to comprehend these problem structures. Therefore, as the next step, we have designed and developed a learning environment for posing one-step multiplication or division word problem in order to let learners acquire a difference between multiplication and division. Developed learning environment and its practical use in an elementary school are reported.
The correlation of infectivity to the length of SV 40 DNA by dilute and undiluted passage was described. DNA was extracted from purified virions by Marmur's method, and propagation of virus was done using VERO cells. The infectivity of SV 40 (simian virus 40) ran parallel with
the length of its DNA. Undiluted passage caused shortening of DNA and decrease in infectivity, but when these undiluted group was passaged dilutely, length of DNA approached the original length and the infectivity
recovered. In undiluted passage group small circular DNAs under 1.0,11_, so far not reported in the SV 40 DNA, were found in low frequency. Replicating form and dimers were also noted from virions and the nuclei of SV 40 infected VERO cells.
Cryptococcosis is a notable infectious complication of liver transplantation. Currently, there is no recommendation for screening serum cryptococcal antigen (CrAg) levels in solid organ transplant recipients. We aimed to explore the role of serum CrAg in liver transplant recipients at an institution where posttransplant serum CrAg has been widely tested.
The emergence and spread of new SARS-CoV-2 variants with mutations in the spike protein, such as the XBB.1.5 and XBB.1.9.1 sublineages, raise concerns about the efficacy of current COVID-19 vaccines and therapeutic monoclonal antibodies (mAbs). In this study, none of the mAbs we tested neutralized XBB.1.9.1 or XBB.1.5, even at the highest concentration used. We also found that the bivalent mRNA vaccine could enhance humoral immunity against XBB.1.9.1, but that XBB.1.9.1 and XBB.1.5 still evaded humoral immunity induced by vaccination or infection. Moreover, the susceptibility of XBB.1.9.1 to remdesivir, molnupiravir, nirmatrelvir, and ensitrelvir was similar to that of the ancestral strain and the XBB.1.5 isolate
Background: Human microbiotas are community of microorganisms, living in symbiosis with humans. They play an important role in the host immune response to respiratory viral infection. However, evidence on the human microbiome and coronavirus disease (COVID-19) relationship is insufficient. This systematic literature review aimed to evaluate existing evidence on the association between the microbiome and COVID-19 in humans and summarize this data in the pandemic era.Methods: We conducted a systematic literature review on the association between the microbiome and COVID-19 in humans by searching PubMed, Embase, and the Cochrane Library, CINAHL, and Web of Science databases for articles in English published up to October 31, 2020. The results were analyzed using qualitative analysis of evidence. This study is registered with PROSPERO (CRD42020195982).Findings: Of the 543 articles identified by searching databases, 16 in line with the research objectives were eligible for qualitative review: eight sampled the microbiome using stool, four using nasopharyngeal or throat swab, three using bronchoalveolar lavage fluid, and one using lung tissue. Fecal microbiome dysbiosis and increased opportunistic pathogens in COVID-19 patients were reported. Several studies suggested the dysbiosis in the lung microbiome of COVID-19 patients with abundance of opportunistic pathogens using lower respiratory tract samples. The association between COVID-19 severity and the human microbiome remains uncertain.Interpretation: The human fecal and respiratory tract microbiome changed in COVID-19 patients with opportunistic pathogen abundance. Further research to elucidate the effect of alternation of the human microbiome in disease pathogenesis is warranted.Funding: This study received no funding.Declaration of Interests: The authors have no conflicts of interest to declare.
